Apparatus for interrupting alternating power circuits



Sept. 5, 1933. CHESNUT 1,925,994

APPARATUS FOR INTERRUPTING ALTERNATING POWER CIRCUITS Filed Feb. 23,1929 Patented Sept. 5, 1933 APPARATUS FOR INTERBUPTING ALTER- NATINGPOWER CIRCUITS Frank T. Chesnut, Trenton, N. 1., assignor to AjaxElectrothermic Corporation, Ajax Park, N. J., a corporation of NewJersey Application February 23, 1929. Serial No. 342,282

6 Claims.

My invention relates to disconnection of alternating current powercircuits.

The main purpose of my invention is to provide for opening a-pluralityof alternating current power circuits one at a time through the samedisconnecting mechanism.

A further purpose' is to provide for throwing a resonated reactance inparallel with the current supplies for alternating current powercircuits, one circuit at a time, then opening the supply to theparticular circuit with which the resonated reactance is in parallel andsubsequently opening the circuit through the resonated reactance andrepeating the operation with the same resonated reactance for the othercircuits as they require disconnection.

Further purposes will appear in the specification and in the claims.

I have illustrated my invention purely diagrammatically and by one formonly, selecting a form which is practical, efficient and thoroughlyreliable and which at the same time well illustrates the principles ofmy invention.

Figure 1 shows diagrammatically a plurality of power circuits withdisconnecting means adapted to be efiective, one at a time, with any ofthem.

Figure 2 shows operation of diagrammatic circuits from a distant point.

The generator 9 is intended to be typical of the different types ofalternating current sources of supply available and is not intended tobe restrictedto the normal rotary generator of commerce.

This generator is shown in Figure 1 as supplying alternating current toa number of power circuits having diflerent characteristics, to indicatethat the application of my invention is independent of the character ofcircuit interrupted. In one of these circuits a resistance load 10 isshown. In a second an inductive load 11 appears, with resistance 10separately shown but intended to include the resistance inherent to theinductive load aswell as any outside resistance which may exist in thecircuit. In the third connection a'resonant circuit is supplied,comprising an inductance 11 and capacity 12. All of these circuits areconnected across current supply lines 13 and 14 through suitableswitches. A wave trap is used which is capable of operation with any ofthe circuits. I have illustrated one such trap comprising a resonatedcircuit having capacity .15 and inductance 16.

The wave trap is adapted to be connected between one of the lines, suchas line 14, and the load, in parallel with the normal connection of thisload with the line so that the same wave trap may be used to parallelthe normal connections between any of the loads and the line.

The character of switch or switches by which the wave trap and thenormal connection .of the load with any line are placed in parallel, oneat a time, for any of the loads, and

by which the connections are subsequently opened, is not important,provided that it is ing the required function; and switch will,therefore,

capable of performthe character of be determined upon the basis of thesimplicity, reliability and convenience of the switch as distinguishedfrom any supposed novelty in the switch types of switches are itself.Two such shown. One is intended to represent a spring contactor but forconvenience of illustration is shown as provided with knives movablelaterally across the contacts.

The loads are shown in Figure 1 as through with the line normallycontacts 18 and conductors 19.

switch arm 1'7 with its contact connected switch arms 1'7,

Each switch arm 1'7 is electrically connected with a switch arm 20 whichis adapted to engage or break contact with a contact 21 without openingthe engagement of 18. A third contact 22 provides convenient restingplace for arm 1'7 when its engagement with contact 18 is broken.

The wave trap is connected between line 14 and the several contacts 21,one for each circuit to be opened.

In operation the current for the loads normally passes through switches1'7, 1'7

and 1'7 and their connections 19. To interrupt the circuit supplying anyof the loads,

such as that through switch 17', the wave trap is connected in parallelwith the corresponding connection switch 20' against contact 21.

through connection 19 can then opening switch 1'7 tion of this switch.This 19, as by closing The current be interrupted by as shown in thedotted posiis permissible because the condenser of the wave trap willtake up the surge which would otherwise cause arcing,

will be distributed in the trouble at the switch.

this surging current wave trap instead of causing The current throughthe wave interrupted by opening the arc. This interruption of to or fromthe wave trap can and trap can then be switch 20' without any thecircuit connection take place at is opened it can be turned dottedposition of t a load a ain in its normal circuit the correspondingswitch 17, 17' or 1'7 is closed.

It is convenient but by no means necessary to couple the switches 17 and20, 17' and 20', 1'7 and 20 respectively so as to permit independentmovement between them throughout a limited rangeof separation and torequire that the two switches shall move together when the limit ofseparation has been exceeded. The separation should be sufficient topermit the two switches to engage contacts 18 and 21, 18' and 21, etc.at the same time, carrying switch 17 with switch 20, for example, incounter-clockwise movement in Figure 1 after the limit of movement hasbeen reached, and closing switch 20 against switch 17, for example, withclockwise movement in the figure so that but one switch need be operatedin each direction. During this last (restoring) movement of the switcharms, switch 20 will momentarily close the circuit through the ,wavetrap unless the circuit meantime be interrupted at some other point.

In the diagram switches 17, 17' and 17 are shorter than switches 20,20', 20 so as to avoid engagement of these switches with the contacts21, 21, 21

In Figure 2 I have applied the invention to parallel operation of anumber of specific devices in the same art, here a plurality of tunedfurnace inductor circuits having inductors 11 and condensers 12 each,each furnace supply circuit of which can be interrupted by the wave trapmechanism common to all.

In order to indicate that the character of switch is not controlling Ihave illustrated different switch mechanism in Figure 2 from that inFigure 1. Figure 2 shows pairs of contactor blades 23 and 24, one pairfor each load circuit. The contactor fingers are spaced by insulatingmaterial 25 and, until the electromagnets are energized, are springretracted by any suitable spring 26.

The contactor blades are electromagnetically operated in any suitableway as by electromagnets 27 whose coils receive current from a line 28through appropriate individual switches 29.

The blades engage contacts 30 and 31 which are so spaced andproportioned that in the position of the blades dotted at 23', 24 bothblades are closed against their contacts while in the position 23 24 theblade 24 is closed against its contact and the blade 23 is open.

When electromagnetically controlled, the load circuit is connected tothe line uninterruptedly through the contact 31, blade 24 and connection32, but when it is desired to open any circuit, deenergization of theelectromagnet 2'? permits the spring 26 to shift both blades to the leftto the position shown in solid lines.

Starting with the switch position shown in solid lines at the left inFigure 1 when the proper electromagnet is energized the switch will movein clockwise direction and will, in passing, momentarily include thewave trap in the circuit during its movement to the final position inwhich the load is connected to the line. This momentary connection takesplace while knife 23 is passing over contact 30 and is notobjectionable. When knife 24 engages contact 31 a part of the loadcircuit is placed in parallel with the wave trap circuit, and thiscondition continues until knife 23 leaves contact 30 and breaks thiswave trap connection. The load circuit path through switch knife 24 andconnection 32 is then the only load circuit path to the line at thispoint. This is the switch position for furnace operation.

When the coil of the electromagnet is deenergized, either throughfailure of current or by opening the appropriate switch, the blades 23and 24 are retracted by the spring, moving in counter-clockwisedirection. By this movement a wave trap similar to that in Figure 1 isfirst introduced in parallel with a portion of the load circuit whichpasses through the switch and connection 32, and the circuit throughconnection 32 is then opened while the wave trap is still connected toreceive and to distribute within the trap the surge of current due tothe opening of the main circuit. The circuit through the wave trap isthen opened and the switch comes to rest in the position shown in Figure2.

As will be seen the automatic control of the succession of contacts madein opening and closing the blades 23 and 24 ensures the proper order ofthese contacts and fully protects against accidental or erroneousconnection of the circuits. Electromagnetic control of the severaldevices permits thorough and reliable control of the circuits at adistance so as not only to open and close the circuits but to ensureinclusion of the wave trap in parallel with the portion of the circuitto be interrupted up to the time of interruption of the main circuit.

It will be evident that I have provided mechanism common to any numberof circuits to be interrupted which will open these circuits withoutsubstantial arcing.

It will be evident that whether a split switch or independent switches,or a multipolar switch be used the function is the same of throwing thecommon wave trap into parallel with the circuit to be interrupted,maintaining the connection through the wave trap while the current pathto the load through the paralleled circuit is interrupted andsubsequently interrupting the wave trap circuit.

In view of my invention and disclosure variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the structure shown, and I, therefore, claimall such in so far as they fall within the reasonable spirit and scopeof my invention.

Having thus described my invention what I claim as new and desire toPatent is:-

1. A plurality of alternating current power circuits in combination witha wave trap circuit containing means common for each of the circuits forinterrupting each of the circuits and 13 means respectively forconnecting the wave trap circuit in parallel with a part of any circuit,for subsequently opening the part of the circuit so paralleled and forfinally opening the circuit through the wave trap.

2. A plurality of alternating current power circuits, in combinationwith a wave trap circuit for interrupting each of the power circuits andmeans respectively for connecting the wave trap circuit in parallel witha part of any circuit, and for subsequently opening the part of thecircuit so paralleled.

3. An alternating current power circuit, a switch in said circuit, awave trap connected to parallel the part of the power circuit containingsaid switch, a switch in the connection to the wave trap, circuitconnections between the two switches whereby, beginning with the switchin the power circuit closed, the wave trap circuit is closed and thepower circuit is subsequently 5 secure by Lett 125,

nating current power circuits, a circuit loop having two parallelbranches, an inductance in one branch, a capacity in the other branch,means for connecting the circuit loop in parallel with a portion of anyone of the power circuits which is to be broken, means for breaking theparalleled portion of the power circuit to which the loop is connectedand means for subsequently disconnecting said power circuit from saidloop.

6. In an electrical system, a plurality of alternating current circuits,a switch in each circuit, a shunting circuit having a resonant loop,means for shunting any one of the switches by the shunting circuit andmeans for removing the shunt from said oneswitch after the switch hasbeen opened.

FRANK T. CHEN'UT.

